The present invention relates to a gas type identification system for identifying the type of gas that flows in a flow path and automatically setting conditions which are suitable for that gas type.
Conventionally, methods are known for utilizing the sound velocity of a gas in a flow rate measurement apparatus for diagnosing the malfunctioning of a flow rate meter. Such a method is described in, for example, Japanese Laid-Open Publication No. 8-304135.
FIG. 1 shows the structure of a flow rate measurement apparatus described in Japanese Laid-Open Publication No. 8-304135.
As shown in FIG. 1, the flow rate measurement apparatus includes an ultrasonic measurement section 1, a sound velocity calculation section 2, a sound velocity setting section 3, a temperature measurement section 4, a sound velocity calculation section 5, and a comparison section 6.
The sound velocity calculation section 2 calculates a sound velocity based on a signal which is output from the ultrasonic measurement section 1. The sound velocity which has been calculated by the sound velocity calculation section 2 is output to the comparison section 6. Based on a temperature signal which is output from the temperature measurement section 4, the sound velocity calculation section 5 performs temperature compensation for a sound velocity which is previously set in the sound velocity setting section 3. The sound velocity which has been subjected to temperature compensation by the sound velocity calculation section 5 is output to the comparison section 6. The comparison section 6 compares the sound velocity which is output from the sound velocity calculation section 2 with the sound velocity which is output from the sound velocity calculation section 5. Based on the comparison result by the comparison section 6, it is determined whether the ultrasonic measurement section 1 is malfunctioning or not.
Thus, conventional systems diagnoses whether or not a flow rate measurement apparatus is malfunctioning under the premise that the type of gas is known. Conventional systems do not identify gas types. Conventional systems do not set conditions according to gas types.
A gas type identification system according to the present invention includes: a flow path; an ultrasonic measurement section disposed in the flow path, the ultrasonic measurement section including a pair of ultrasonic transducers; a sound velocity calculation section for calculating a sound velocity of a gas flowing through the flow path based on a signal from the ultrasonic measurement section; a sound velocity memory section for previously storing a predetermined sound velocity; and a comparison section for comparing the sound velocity calculated by the sound velocity calculation section with the predetermined sound velocity previously stored in the sound velocity memory section.
In one embodiment of the invention, the gas type identification system further includes: a flow rate compensation coefficient setting section for setting a flow rate compensation coefficient in accordance with a result of the comparison by the comparison section; and a flow rate calculation section for calculating a flow rate of the gas flowing through the flow path based on the signal from the ultrasonic measurement section and the flow rate compensation coefficient.
In another embodiment of the invention, the gas type identification system further includes: a dual mode valve disposed in the flow path; and a control section for controlling the dual mode valve in accordance with a result of the comparison by the comparison section.
In still another embodiment of the invention, the gas type identification system further includes: a dual mode valve disposed in the flow path; a safety standards setting section for setting safety standards in accordance with a result of the comparison by the comparison section; a determination section for determining whether or not the safety standards are satisfied; and a control section for controlling the dual mode valve in accordance with a result of the determination by the determination section.
Alternatively, the gas type identification system according to the present invention includes: a flow path; a temperature measurement section disposed in the flow path; a temperature calculation section for calculating a temperature of a gas flowing through the flow path based on a signal from the temperature measurement section; an ultrasonic measurement section disposed in the flow path, the ultrasonic measurement section including a pair of ultrasonic transducers; a sound velocity calculation section for calculating a sound velocity of the gas flowing through the flow path based on a signal from the ultrasonic measurement section; a temperature/sound velocity memory section for previously storing a predetermined temperature and a predetermined sound velocity; and a comparison section for comparing the temperature calculated by the temperature calculation section with the predetermined temperature previously stored in the temperature/sound velocity memory section and comparing the sound velocity calculated by the sound velocity calculation section with the predetermined sound velocity previously stored in the temperature/sound velocity memory section.
In one embodiment of the invention, the gas type identification system further includes: a flow rate compensation coefficient setting section for setting a flow rate compensation coefficient in accordance with a result of the comparison by the comparison section; and a flow rate calculation section for calculating a flow rate of the gas flowing through the flow path based on the signal from the ultrasonic measurement section and the flow rate compensation coefficient.
In another embodiment of the invention, the gas type identification system further includes: a dual mode valve disposed in the flow path; and a control section for controlling the dual mode valve in accordance with a result of the comparison by the comparison section.
In still another embodiment of the invention, the gas type identification system further includes: a dual mode valve disposed in the flow path; a safety standards setting section for setting safety standards in accordance with a result of the comparison by the comparison section; a determination section for determining whether or not the safety standards are satisfied; and a control section for controlling the dual mode valve in accordance with a result of the determination by the determination section.
Alternatively, the gas type identification system according to the present invention includes: a flow path; a temperature measurement section disposed in the flow path; a temperature calculation section for calculating a first temperature and a second temperature of a gas flowing through the flow path based on a signal from the temperature measurement section; an ultrasonic measurement section disposed in the flow path, the ultrasonic measurement section including a pair of ultrasonic transducers; a sound velocity calculation section for calculating a first sound velocity and a second sound velocity of the gas flowing through the flow path based on a signal from the ultrasonic measurement section; a temperature/sound velocity memory section for previously storing a predetermined temperature and a predetermined sound velocity; and a comparison section for comparing the first temperature and the second temperature calculated by the temperature calculation section with the predetermined temperature previously stored in the temperature/sound velocity memory section and comparing the first sound velocity and the second sound velocity calculated by the sound velocity calculation section with the predetermined sound velocity previously stored in the temperature/sound velocity memory section.
In one embodiment of the invention, the gas type identification system further includes: a flow rate compensation coefficient setting section for setting a flow rate compensation coefficient in accordance with a result of the comparison by the comparison section; and a flow rate calculation section for calculating a flow rate of the gas flowing through the flow path based on the signal from the ultrasonic measurement section and the flow rate compensation coefficient.
In another embodiment of the invention, the gas type identification system further includes: a dual mode valve disposed in the flow path; and a control section for controlling the dual mode valve in accordance with a result of the comparison by the comparison section.
In still another embodiment of the invention, the gas type identification system further includes: a dual mode valve disposed in the flow path; a safety standards setting section for setting safety standards in accordance with a result of the comparison by the comparison section; a determination section for determining whether or not the safety standards are satisfied; and a control section for controlling the dual mode valve in accordance with a result of the determination by the determination section.
Thus, the invention described herein makes possible the advantage of providing a gas type identification system which identifies the type of gas that flows in a flow path and automatically sets conditions which are suitable for that gas type.